Thermionic valve



Dec. 15, 1925- w. R. BULLIMORE THERMIONIC VALVE Filed Oct 11, 1922 2 Sheets-Sheet 1 Dec 15,1925- W. R. BULLIMORE THERMIONIC VALVE Filed Oct. 11 1922 2 Sheets-Sheet 2 STATES FFICEQ BIOH ABD summons, LOI Q'DON, ENGLAND.

rmrnmomc VALVE.

Animat on fled cam: n, ma; Serial m5. roam.

To all whom it may concern:

Be it known a that I, WILLIAM Rrcrmnn BULLmonn, a subject of the King of Great posed as a controlling sagging of the filament as t In wireless telephony, considerable stress is Britain and Ireland, residin at Aberdeen Lane, Highbury Grove, Lon on, N. 5, England, have invented new and useful Improvements in Thermionic Valves (for which have made application for Letters Patent of Great Britain, No. 17,232, filed J um 22, 1922), of which the following is a specification.

This invention relates to improvements in thermionic valves, havin more particular reference to those of the tfi principally employed for wireless telephony and telegraphy, in which a grid is intered filament and an anode.

The object of the invention is to provide a thermionic valve in which a heated .fila-' ment, a id electrode and an anode are so assemble as to ensure total utilization of electron emission and preserve during use constant or practically constant interspacing of the electrodes.

In the present invention, correct interspacing of the electrodes is not only maintained, but by the special construction em- .ployed, rendered more secure against vibration of the grid or anode or drooping or he result of use.

laid upon the necessity of eliminatinglmicrophonic noises due to vibration-of t e electrodes and this can only be achieved by rigid mounting ofthe res ctive parts and maintenanceof such rigi ity against considerable movement or vibration external to the bulb or evacuated vitreous container of the valve.

According to the resent invention a thermionic valve of t e three electrode t e comprises an. arched filament, an arc ed grid having flattened sides enclosing the filai ment and an anode of similar sha e to and of larger dimensions than the grid enclosing both filament and grid, .all of the elec:

- trodes being independently and rigidly supported from one or more re-entrant-tube's of a vitreous container. According to the preferred method of construction the grid electrode is formed from a collar having arallel sides and rounded ends and means or securin thereto a number of wire loops the to s 0 which form an arch concentric with e filament.

ree electrode type device between a heat- ,2 the grid and. 3 the anode.

"Reference will now be made to the accompanying drawings which illustrate by.

way of exam 1e 9. thermionic valve constructed accor ing to the invention and in 1 is an elevation partly in section,

Fig. 2 is. an elevation partly in section looking in a direction at right angles to Fig 1,

V ig. 3 is a ers ective view of the grid on an enlarge Fig. 4 is an elevation showing the a plication of the invention to a container h scae,"

avin two re-entrant tubes and ig. 5 is a view of a modified construction of grid. I

In the drawings, 1 is the cathode filament, The filament is mounted between two conductors 4 in such a manner as to form an arch which may be nearly semicircular or of similar form, but is arranged preferably so that the 1 distance between the terminal ends is less 4 1,565,708' PATENT o having parallel sides and curved ends (see'= Fig. 3). The collar in its unassembled state is. formed with castellations on its upper, edge which are subsequently bent over to provide hooks 8.

Accordin to one form, the grid meshisformed as s own in Fi 3 from a continuv ous length of wire w 'ch' is laced alter-Q- I nately under hooks on opposite sides of the aid forming loops 9 which extend overthe ament 1 and are of such length that the curvature of the top of the finished grid- .is

concentric with that of the filament. The, .ends of the grid wires and'the'loops 9 are permanentlysecured in place by'closing the ooks 8 or b hooks 8 and y tain' the loops!) in parallel positions a bracing wire 10 secured at its ends to the curved end portions of the collar 7 may be emspotwelding or by closing thg spot' welding whilstto main ployed which concentrically I as ' i around the loops 9 at their uppermost points or may be secured thereto as by spot welding. Additional bracin wires may be employed if desired to sti en the vertical portions of the loops 9. One of the parallel sides of the collar 7 is formed with a lug or socket 11 for attachment to a stron supporting conducto -12 sealed into t e reentrant tube 5.21: An alternative method of constructing the grid is to pierce holes in the supporting collar 7 in place of the castellations and to thread the wire forming the loops 9 through such, holes and fix them by spot welding or other appropriate means.

According to another form the grid may be made by stamping slots 14: from sheet metal to the form shown in Fig. 5.

Over the grid is disposed the t anode 3 which preferably consists in a sheet metal stamping of larger dimensions than the grid 2 but following'closely the shape of the latter. The anode is mounted on a support 13- constituting also an electrical conductor and sealed into the re-entrant tube 5.

In an alternative method of construction a vitreous container (see Fig. 4) having two,

p with the ormation and disposition of the electrodes described practically the whole of the electron emission from the filament is utilized and electrification of the glass is reduced to a minimum. Further it is free from microphom'c disturbances and the filament and several electrodes maintain theirparallelism despite frequent and prolonged use. Moreover, consistent with the results,

obtained, it is more economical to manufacture and can be produced in bulk with a high degree of uniformity.

1 claim 2- I 1. A thermionic valve comprising a vitreous container, an arched cathode filament, a hollow id electrode enclosing said filament and iaving fiat sides meeting alon a curved edge disposed parallel to said ament, an anode of similar shape to' and of larger dimensions than said grid electrode enclosing said filament and grid electrode and means for inde endently and rigidly supportin all of said electrodes from a re entrant tu e in said vitreous container.

2. A thermionic valve comprising a vitreous container, re-entrant tubes formed therein, an arched cathode filament, a hollow grid electrode enclosing said filament and having fiat sides meeting alon a curved edge disposed parallel to said ament, an anode of weaves sides and roun ed ends with means for se-- curing thereto said wire loops, the tops of said loops forming an arch concentric with the filament, an anode enclosin said filament and grid and means for in ependently and rigidly supporting all of said electrodes from said re-entrant tube.

4. A thermionic valve comprising a vitreous container, a re-entrant tube formed .therein, an arched cathode filament, a grid electrode comprising a collar having parallel sides and rounded ends, a series of castellations around the upper edge or" said collar, hooks formed on said castellations and wire laced around said hooks to form closing-said filament and id and means for independently supportlng all or" said electrodes from said re-entrant tube.

5. A thermionic valve comprising a vitreous container, a .re-entrant tube formed therein, av plurality V of rigid conductors sealed into. said container through saidtube, a hollow sheet metal anode having parallel sides meeting along an arched edge mounted on one of said conductors, a hol- -low arched grid electrede mounted within said anode on another of said conductors and an arched filament enclosed by said grid electrode and carried by two of conductors.

loops enclosing said filament, an anode enion 6. A thermionic valve avitreous container, an arched cathode filament mounted therem, a hollow grid electrode having fiat sides meeting along a curved edge disposed parallel to said filament, said 1d electrode being formed of looped wires enc osmg said filament and a sheet metal anode of similar shape to and of larger dimensions than sai g aid enclosing both filament and grid.

thermionic valve comprising a vitreous container, are-entrant tube formed therein,'an-arciiedjcathode filament, a grid electrode comprising a collar having parallel sides and rounded ends a series of hooks formed round the edge c said collar, wire laced around said hooks to form a series of loops enclosing said filament, a sheet metal anode of similar shape and of lar er dimensions than said grid electrode enc osing said grid and filament and rigid conductors sealed in through said re-entrant tubes carrying said electrodes in rigid eguispaced relationshipo are 1,565,7oe a 8. A thermionic nlve comprising -a vitrethan said grid enclosing both filament and i one container, an arched csthode filament grid and means supporting said electrodes mounted therein, a hollow wire grid elec- 1n rigid equispwed relationship within-said 10 trode enclosing said filsment having flat vitreous oontemer.

' I sides meeting along a curved edge disposed In witnew whereof I sfix my aignnture.

pernllel to and filament, a'. sheet metal anode of shepe to me of larger dimensions WILLIAM 1110mm) BULLIMORE. 

